Oral malodor, plaque, gingivitis, periodontal disease, and discoloration of the teeth, are all undesirable conditions that affect many people. First malodor of the oral cavity is also known as halitosis or bad breath. It is broadly estimated in the U.S. that 20-90 million individuals have oral malodor. It is generally believed that the cause of this condition is due to the presence of anaerobic bacteria, especially gram-negative anaerobic bacteria, in the mouth. These bacteria will generate volatile sulfur compounds (VSC) which are known to cause breath malodor.
It is recognized in the art that some breath malodor is caused by three chemical compounds. Specifically, these compounds are hydrogen sulfide (H--S--H), methyl mercaptan (CH.sub.3 --S--H) and dimethyl sulfide (CH.sub.2 --S--CH.sub.3). These compounds result from the degradation of epithelial cells and bacteria in the oral cavity. Specifically, the polypeptide chains of the epithelial cell walls, are composed of a series of amino acids including cysteine and methionine which contain sulfur side chains. The death of microorganisms or epithelial cells results in degradation of the polypeptide chains into their amino acid components, especially cysteine and methionine. Cysteine and methionine are precursors to the formation of VSC.
It is also recognized in the art that oral malodor not only comes from the posterior dorsal surface of the tongue but also from periodontal pockets. Furthermore, a person with gingivitis or periodontal disease may have increased oral malodor from disintegrated epithelial cells. Epithelial cells turn over faster if inflammation is present. Therefore, a larger number of these dead epithelial cells remain in the oral cavity and will degrade into the malodorous compounds.
In addition VSC will also alter the epithelial barrier, permitting penetration of the barrier by antigenic substances. For example, VSC such as hydrogen sulfide, methyl mercaptan and dimethyl sulfide contribute to the penetration of bacterial toxins through the epithelial barrier into the underlying basal lamina and connective tissue. A. Rizzo, Peridontics, 5: 233-236 (1967); W. Ng and J. Tonzetich, J. Dental Research, 63(7): 994-997 (1984); M. C. Solis-Gaffar, T. J. Fischer and A. Gaffar, J. Soc. Cosmetic Chem., 30: 241-247 (1979). Thereafter, bacterial toxins, bacteria and virus can invade the underlying gingival tissue adjacent to the sulcular space, thereafter invading the underlying connective tissue. A decrease in VSC will decrease the tissue permeability to oral toxins and bacteria.
Systemic entities can contribute to oral malodor as well. These entities include oral carcinomas, diabetes, liver and kidney abnormalities, medications which change the oral environment, ENT problems such as chronic sinusitis, tonsillitis and inflamed adenoids. Gastrointestinal problems do not contribute to chronic oral malodor, although this is a common belief. Evaluation and diagnosis of oral malodor can be achieved with the Halimeter (Interscan). The Halimeter is a gas-analysis sensor that measures the volatile sulfur compounds in breath.
Furthermore, periodontal disease is also an undesirable condition which has widespread occurrence. Periodontal disease is a major cause of tooth loss in adults, beginning as early as age 12. Even by age 15, it is possible that 4 out of 5 persons already have gingivitis and possibly as many as 4 out of 10 have periodontitis.
Periodontal disease affects the periodontum, which is the investing and supporting tissues surrounding a tooth (i.e., the periodontal ligament, the gingiva, and the alveolar bone). Gingivitis and periodontitis are inflammatory disorders of the gingiva and the deeper periodontal tissues, respectively.
It is well accepted that periodontal disease is associated with the accumulation of plaque on the teeth. The teeth are coated with a salivary proteanaceous material (pellicle) and thereafter streptococci adhere to this coating. Gingivitis occurs from the dental plaque, and periodontitis is caused by the infection spreading to the periodontal pocket or space between the gingiva and the tooth root.
Furthermore, consumers are very interested in making their teeth whiter. Consumers consider people with whiter teeth as having more personal confidence and better social acceptance.
Teeth comprise both an inner dentin layer and an outer hard enamel layer. The enamel layer protects the inner dentin layer and live tissue and serves as the contact surface for mastication of solid food. The enamel layer is generally translucent and slightly off-white in color. It is also considered porous since the hydroxy apatite crystals that comprise the enamel form microscopic hexagonal rods or prisms having microscopic pores or channels between them. As a result of this porous structure, staining agents and discoloring substances, such as antibiotics, foods containing coloring materials, coffee, cola, tea, tabacco, etc., can permeate the enamel and change its surface to appear yellow or brownish in color.
While good oral hygiene, as achieved by brushing the teeth with a cleansing dentifrice, may help reduce the incidence of stain, gingivitis, plaque, periodontal disease, and/or breath malodor, it does not necessarily prevent or eliminate their occurrence. Microorganisms contribute to both the initiation and progression of gingivitis, plaque, periodontal disease, and/or breath malodor. Thus, in order to prevent or treat these conditions, these microorganisms must be suppressed by some means other than simple mechanical scrubbing. In addition, simple mechanical scrubbing will not be entirely effective to remove all stain types and/or whiten the teeth.
Towards this end, a great deal of research has been aimed at developing therapeutic compositions and methods of treating the above conditions, that are effective in suppressing microorganisms. Also, research has been aimed at developing effective whitening compositions. Some of this research has focused on oral care compositions and methods comprising chlorine dioxide or chlorine dioxide generating compounds. Chlorine dioxide is a very strong oxidant and is known as a broad spectrum antimicrobial agent.
The prior art discloses compositions and methods that use chlorine dioxide for the treatment of various oral care conditions. Most of these prior art references teach that the delivery of chlorine dioxide is essential to provide efficacy. This is in contrast to the present invention which focuses on the delivery of chlorite ion to the oral cavity, to provide efficacy. The compositions and methods of the present invention are specifically and intentionally designed to avoid or minimize the production of chlorine dioxide in the compositions.
The prior art teaches a variety of ways to deliver chlorine dioxide, in oral care compositions, to the oral cavity. For example, U.S. Pat. No. 4,689,215 issued Aug. 25, 1987; U.S. Pat. No. 4,837,009 issued Jun. 6, 1989; U.S. Pat. No. 4,696,811, issued Sep. 29, 1987; U.S. Pat. No. 4,808,389 issued Feb. 28, 1989; U.S. Pat. No. 4,786,492 issued Nov. 22, 1988; U.S. Pat. No. 4,788,053 issued Nov. 29, 1988; U.S. Pat. No. 4,792,442 issued Dec. 20, 1988; U.S. Pat. No. 4,818,519 issued Apr. 4, 1989; U.S. Pat. No. 4,851,21 issued Jul. 25, 1989; U.S. Pat. No. 4,855,135 issued Aug. 8, 1989; U.S. Pat. No. 4,793,989 issued Dec. 27, 1988; U.S. Pat. No. 4,886,657 issued Dec. 12, 1989; U.S. Pat. No. 4,889,714 issued Dec. 26, 1989; U.S. Pat. No. 4,925,656 issued May 15, 1990; U.S. Pat. No. 4,975,285 issued Dec. 4, 1990; U.S. Pat. No. 4,978,535 issued Dec. 18, 1990; U.S. Pat. No. 5,200,171 issued Apr. 6, 1993; U.S. Pat. No. 5,348,734 issued Sep. 20, 1994; U.S. Pat. No. 5,618,550 issued Apr. 8, 1997, and U.S. Pat. No. 5,489,435 issued Feb. 6, 1996, all to Perry A. Ratcliffe, teach oral care compositions and methods of treatment using stabilized chlorine dioxide.
Additional prior art references, which teach the generation and delivery of chlorine dioxide with activator compounds such as protic acids, reducing sugar activators, etc., include: U.S. Pat. No. 5,281,412, Lukacovic et al., issued Jan. 25, 1994, The Procter & Gamble Co.; U.S. Pat. No. 5,110,652, Kross et al., issued Mar. 31, 1992, Alcide Corporation; U.S. Pat. No. 5,019,402, Kross et al., issued May 28, 1991, Alcide; U.S. Pat. No. 4,986,990, Davidson et al., issued Jan. 22, 1991, Alcide; U.S. Pat. No. 4,891,216, Kross et al., issued Jan. 2, 1990, Alcide; U.S. Pat. No. 4,330,531, Alliger, issued May 18, 1982; DE 2,329,753, published Dec. 13, 1973, National Patent Development Corp.; EP 287,074, Kross et al., published Oct. 19, 1988, Alcide; EP 565,134, Kross et al., published Oct. 13, 1993, Alcide; and WO/95/27472, Richter, published Oct. 19, 1995.
Additional prior art references relating to chlorine dioxide compositions include: GB 2,289,841, Mehmet, published Jun. 12, 1995, Janina International; GB 2,290,233, Drayson et al., published Dec. 20, 1995, Medical Express Limited; WO 96/25916, Van Den Bosch et al., published Aug. 29, 1996, Diamond White; JP 054,311, Tsuchikura, published Mar. 28, 1985; JP 105,610, Tsuchikura, published Jun. 11, 1985; and WO/89/03179, Partlow et al., published Apr. 20, 1989, New Generation Products. All of the above references are incorporated herein by reference in their entirety.
The above prior art references have not recognized that the delivery of chlorite ion, itself, to the oral cavity will provide efficacy in various oral care conditions. Because prior art references have focused on the delivery of chlorine dioxide for efficacy, prior art compositions and methods of treatment may have various drawbacks. For example, compositions comprising chlorine dioxide can exhibit aesthetic disadvantages such as "chlorine" (e.g. swimming pool) taste and smell. In addition due to the strong oxidizing capability of chlorine dioxide, compositions comprising chlorine dioxide may have certain stability disadvantages, especially in oral care formulations.
Therefore, prior art compositions, mentioned above, have not been entirely satisfactory for the treatment and/or prevention of gingivitis, plaque, periodontal disease, and/or breath malodor or for the whitening of teeth. Therefore, additional efficacious compositions and methods of treatment for these purposes are desirable.
As mentioned above, the present invention relates to the delivery of chlorite ion to the oral cavity for efficacy. The present invention is specifically designed to avoid or minimize the production of chlorine dioxide or chlorous acid in the compositions. The present invention, therefore, relates to oral care compositions comprising chlorite ion wherein no (or only very low levels of) chlorine dioxide or chlorous acid is generated or is present in the oral care compositions at the time of use. Moreover, the present invention preferably relates to oral care compositions comprising chlorite ion with relatively alkaline pHs, e.g. at pHs above 7, whereby no (or only very low levels of) chlorine dioxide or chlorous acid is generated or is present in the oral care composition at the time of use. Further, compositions of the present invention comprise at least a minimum amount of chlorite ion for effectiveness. These compositions and methods (of the present invention) are effective even though no (or only very low levels of) chlorine dioxide or chlorous acid is generated or is present in these compositions.
It is the purpose of the present invention to provide compositions and methods for treating or preventing diseases of the oral cavity, such as plaque, gingivitis, periodontal disease, and for treating or preventing other conditions such as breath malodor, in humans or other animals, by utilizing an effective amount of chlorite ion wherein no (or only very low levels of) chlorine dioxide or chlorous acid is generated or is present in the oral care composition at the time of use. The pH of the final composition is preferably alkaline, e.g. above pH 7.
It is also the purpose of the present invention to provide compositions and methods to whiten teeth, in humans or other animals, by utilizing an effective amount of chlorite ion wherein no (or only very low levels of) chlorine dioxide or chlorous acid is generated or is present in the oral care composition at the time of use. The pH of the final composition is preferably alkaline, e.g. above pH 7.
Further, the present invention relates to oral care compositions, including therapeutic rinses, especially mouth rinses, as well as toothpastes, tooth gels, tooth powders, non-abrasive gels, chewing gums, mouth sprays, and lozenges (including breath mints). These compositions comprise a minimally effective amount of chlorite ion.
These compositions are effective in killing, and/or altering the bacterial metabolism, and/or for a period of time suppressing the growth of, microorganisms which cause topically-treatable infections and diseases of the oral cavity, such as plaque, gingivitis, periodontal disease, and breath malodor. These compositions are also effective to whiten teeth.